1. Field of the Invention
The present invention relates to a sleep diagnosis device which is used for diagnosing sleep apnea syndrome (SAS) and so on.
2. Description of the Related Art
In recent years, there have been a lot of social concerns in sleep apnea syndrome. In a test for sleep apnea syndrome, many sensors, such as temperature sensors for detecting breath from the nose and mouth, a tracheal sound sensor for detecting a snore, a respiration sensor for measuring a breathing movement, a body position sensor for detecting a posture of a patient, and a heart beat sensor for measuring heartbeat, are used.
In a conventional inspection apparatus for sleep apnea syndrome, in order to measure a breathing movement of a patient, strain gauges in a form of a band are wrapped around a chest and a belly (abdomen), and a phase difference between a motion of the chest and a motion of the belly and a magnitude of these motions are measured, and based on the measurement result and a detection result of the breath from the nose and mouth, a type of apnea, for example, central apnea or obstructive apnea, is judged. Or, in another inspection apparatus, pressure sensors are attached to a chest and a belly of a patient to measure a breathing movement of the patient.
Therefore, such a conventional inspection apparatus is burdensome for a patient to whom various sensors are attached, so it is expected to reduce the number of sensors as much as possible and to ease the burden of the patient.
By the way, Japanese Non-examined Patent Publication No. 2005-230511 discloses a sleep apnea syndrome control device. In this device, one-dimensional acceleration sensors are attached to a chest and a belly of a patient to detect a breathing movement of the patient.
However, because motions of the chest and the belly by a breathing movement vary from person to person, an evaluation of the breathing movement based on the acceleration of one direction was inadequate. Furthermore, in the above invention, it is necessary to separately prepare a pressure-sensitive sheet on a mat to detect a posture (a sleeping posture) of the patient.